Friction clutch



Oct. 18 1927.

C. A. STICKNEY FRICTION CLUTCH 2 Sheets-Sheet 1 Filed 001'.. 19, 1925Oct. 18,1927. -1,645,780

C. A. STICKNEY FRICTION CLUTCH 2 Sheets-Sheet 2 ,w a G s, V3 a l.. P f wf7 LJ .x ./^^^^^^\\\\\\H l 0 z 6 7. 7 3 3 .rd 3 n a. 3 3. A@ j n f y ,AHx w w m In j M Z Patented Oct. 18, 1927.

UNITED STATES PATENT oFF-ICE.

CHARLES A. STICKNEY, OF ROCKFORD, ILLINOIS, .ASSIGNOR T ROCKFORDDRILLING MACHINE COMPANY, OF ROCKFORD, ILLINOIS, A CORPORATION OFILLINOIS.

'vrnrorIoN CLUTCH. s

Application led October 19,l 1925.. Serial No. 63,205.

This invention relates to a friction clutch of the disc type especiallyadapted for motor vehicles.

The principal object of the invention is to .i provide a clutch soconstructed as to avoid objectionable grabbing and chattering inoperationA and to afford smooth and quiet running, by the provision ofmeans for securing engagement of the clutch in two stages;

lo in the first sta e the lplates being held in engagement under lightpressure to permit a certain amount of slippage, and in the.

second and nal stage the plates being held in engagement under heavierpressure which does not permit of any appreciable slippage. In carryingout the above object- I provide a main pressure plate havingcomparatively heavy springs to bear thereon to hold thel driving anddriven discs or other' members firmly engaged without slippage, and anauxiliary or intermediate pressure plate having comparatively lightsprings bearing on the same to hold the discs in less secure engagementupon the initial power take-up to permit of a certain amount ofslippage, the auxiliary pressure plate being mounted on the mainpressure plate to be capable of a certain amount of movement awayfromthe main pressure' plate with the light springs acting thereon toengage the auxiliary Aplate first under the light spring pressure,whereupon, when the main plate is brought into engagement, the heavyspringsacting thereon secure the final engagement of the clutch.Referring now to the drawin illustrating my invention, Fig. 1 is aT reareIevation of a iig wheel having my improved clutch mounte thereon; v

Figs. 2 and 3 are enlarged `fragmentary sectional details taken on thelines 2-2 and 3 3 of Fig. 1; y* t Fig. 4 is an enlarged central verticallongitudinal'section through the clutch and,

Hy wheel, taken on the line 4 4 of Fig. l, the clutch being shown infully engaged condition; and

Figs.5 and 6 are fragmentary sectional)y details to illustrate thecompletely disengaged and partially engaged conditions of the clutch.

Throughout the views the same reference numerals are applied tocorresponding parts,

as the parts are referred to in the course of l the follovvindescription, and thetsections are taken loo 'ng in the directionsindicated4 usually provided on therear end of thecrank shaft, therebeing bolts passing throu h the -coupling flange and the web 12 on t efly wheel. The fly wheel 10 may be regarded as the drivingelement. Ashaft 13 constitutes the driven element and ordinarily eX- tendsrearwardly into the gear box of the transmission. A collar 14 is splinedon the shaft 13 and supports one or more driven discs 15 having liningmembers 16 on opposite faces thereof. A ring shaped plate 17 isdisposedbehind the driven disc 15 and is arranged to hold the same Winclose frictional engagement with the driving face 18 on the fly wheel10. It is commonv practice to provide a back plate 19 secured by bolts20 or' other means td the flange 11 on the ily wheel. A plurality ofsprings 21 operate between the pressure plate 17 and the back plate tourge the pressure plate 17 normally under considerable pressure to keepthe driving and driven elements firml engaged. This arrangement,however, ma es no allowance for the fact that unevennessesN arise in thewearing of the linings on theA driving and driven elements, and thatmechanical imperfections are bound to occur, which will prevent smoothand even power take-u when the clutch .is engaged. As a matter o fact itis commonly known that clutches grab and fchatter very frequently,despite painstaking driving relation to the driving element. For thispurpose I provide means for engaging the driven element with the drivingelement by stages; in the first stage of engagement the driving anddriven elements are engaged under light spring pressure permitting acert-ain amount o slippage, and in the second and final stage ofengagement the elements are engaged under a comparatively heavy pressurewhich permit of no appreciable sli pa e.

rocgzeeding now to a more detailed de-` 22 as shown most clearly in Fig.4. The

lugs 2,3 are received'in recesses 24 provided by overlying lugs 25provided on the plate 17. As shown in Fig. 1, three lugs 25 are recessesare suiiiciently wide to permit the` 3 5', extending through thebifurcated ends' rovided in evenly spaced relation. Y The Fugsarebrought into operative relation by rst placing the plates togetherwith the lugs v23 lying between the lugs 25. The plates are then givenrelativerotation until the lugs 23 lie within the recesses 24. The

plate 22 separating from the platei17 to the extent shown in Fig. 5.\The two plates are,

-however, prevented from relative rotation by a plurality of pins .26.These enga e in sockets 27 provided in the plate 22 an are secured inopenings 28 provided in the plate 17. Dowel pins 29 are entered inradial openings 30 in the plate 17 to fasten the pins 26 with theenlarged rear ends 31- thereof lying against the rear side of the plate17 as shown. The rear `ends of the pins 26 are slidably received inopenings 32 :plxlpvided in the back plate 19, and are bicated, as shownat 33, toreceive radially extending levers 34. The latter havepivotal'movement with respect to the ins 26 onpins 33 of the pins 26. The levershave their outer ends provided with adjustable set` screws 36, arrangedwhen 'properly adjusted to be locked by nuts 37. he screws 36 en- 'gagebearing balls 38 set in countersunk openings 39 in the back plate 19.The inner .ends of the levers are operated by a thrust bearing 40provided on the throws out sleeve 41, which has the usual form of clutchcollar 42 to receive the forked end of the clutch lever. From the.description thus far, it will be seen `that the mainpressure plate 17is arranged to be operated posi'- tively by the levers 34 and that theauxiliary pressure plate 22 has, in e'ect, a lostmotion connection withthe Aplate 17, so far as its movement in andv out therewith is concernedfor the engagement and disengagement of the clutch.

The plate 22 is normally urged away from the plate y17 inthe directionof the driven dise 15 by a' plurality of light compression' springs 43,received in re 'stering recesses 44 and 45 in the plates 1 and 22respectively. v These springs serve normally to hold the plates 17 and22 separated to the extent shown in Fig. 5. As a result, when the mainpressure plate 17 is given an initial' ment with the plate 22 and forcesit un er heavy pressure against the disc 15. The springs-43 arecomparatively light and as villustrated in Fig. 1,'it is contempla to4provide a relatively small number of these springs compared with thenumber of springs 21 provided. The springs 21, it will be noted, are setin thimbles 46 received in suitable openings 47 in the back plate 19 andengaged in suitable sockets 48 in the plate 17. Obviously, the initialengageig. 6. It is not until the ment of the clutch under the lightpressure of the springs 43 willpermit a certain amount of s 'ppage andthere will be a gradual power take-upby the shaft 13 until thecomparatively heavy springs 21 come into o ration, after which no moreappreciable s ippage can occur. It is believed obvious from theforegoing that the two sets of springs need not be capable of exerting.

different loads. Approximately the same results wouldfbe secured if theone set served simply fr the initial engagement to provide lightpressure and the other set served to au ment 'the load for finalengagement.y An a vantage of the arrangement, 'aside from its utility inpreventing chattering and grabbing, 1s that there isr avoided theobjectionable spinnilig of the gears in ear shifting u n disengaging theclutch. is is due to t e fact that, as thereis a radual engagement ofthe clutch, there is 'kewise a gradual disengagement; the light springs43 serving in a measure to exert a retarding or checking effect duringlthe disengaging operation. This feature arises from the fact that, as isWell known, the car is accelerated with the gears vin mesh, and, duringthe process of sh1fting from one gear to another, the foot is removedfrom the accelerator pedal, causing anl instantaneous ,decrease in,speed of the engineand consequent- `ly ofthe fly wheel and clutch. Theremoving of the foot from the accelerator pedal is usually pro rly timedwith the releasing of the clutch y experienced drivers to take advantageof the slowing of theengine to stop .the Spinnin of the gears with ltheclutch.Vv It is Vbehlwed that my invention takes more complete advantageof the slowing down of the engine dueto' the time lag in disengagingresulting from the lost motion relation of the auxiliary pressure platewith the main pressure plate.

While I have described my invention as applied to a particularembodiment it is to be understood that.' various other structures may bedevised securing substantially the same results and, also, the inventionmust not be regarded as applicable solely to friction clutches orfriction clutches of the plate or disc type. The accompanying claims arenot therefore to be construed as limiting the invention in any manner tothe speciiic embodiment illustrated. v

I claim:

1. In a friction clutch, a driving member,

` such as a Hy wheel, a driven member, a back plate on said Hy wheel, apressure plate bei tween said back plate andsaid driven member, a mainpressure spring between said pressure plate and said back plate forurging saidv pressure plate toward said driven member, an intermediatepressure plate between said main pressure plate and -said driven member,an auxiliary pressure spring acting between said main` pressure plateand said intermediate pressure plate serving normally to hold the sameseparated and to urge said intermediate pressure plate toward saiddriven member, and means for operating said clutch whereby to engagesaid intermediate pressure plate first under the sole pressure of theauxiliary spring and afterwards said main pressure plate with saiddriven member under the combined pressure ofl both sprin s.

2. n a friction clutch, a driving member, such as a Hy wheel, a drivenmember, a back plate on said Hy wheel, a pressure plate between saidback plate and said driven member, comparatively heavy pressure springsbetween said pressure plate and said back plate for urgingssaid pressureplate toward said driven member, an intermediate pressure plate betweensaid main pressure plate and said driven member, means connecting saidpressure plates to permit 'slight separation thereof but preventingrelative rotation therebetween, comparatively light presf sure springsacting between said mam pressure plate and said intermediate pressureplate serving normally, to hold the same separated and to urgesaidintermediate pressure plate toward said driven member, and means foroperating said clutchwhereby to engage said intermediate pressure platefirst and afterwards said main pressure plate with said driven member.

3. In a friction clutch, a drivingmember, such as a Hy wheel, a drivenmember, such as a clutch plate, a back plate on said Hy wheel, a `twopart pressure plate .between said back plate and said clutch plate, thetwo lugs on one part and lugs on the other parts providing registeringrecesses therein, la first set of pressure springs seated in saidrecesses for urging the forward part of said pressure plate away fromthe rearward part toward the clutchplate, registering recesses in saidrearward part and back plate, a second set of pressure springs disposedin said recesses to urge the rearward part forward toward the clutchplate, the springs of the second set being lheavier than those of theHrst set whereby to overcome the resistance thereof when holding thedriving and driven members in full engagement under heavy pressure,means interconnecting the two parts of said pressure plate so thatftheforward part comes into engagement with the driven member Hr'st and isremoved from engagement last, and means acting between said back plateand said pressure plate for retracting the rearward part against theaction of the second set of springs and for moving the forward part withthe rearward part or permitting both parts to move to-l ward theirengaged positions, said means comprising elements for preventing'relative' rotation between the forward and rearward parts of saidpressure plate or between the pressure plate as a whole and the backplate.

4;. A clutch structure as set forth in claim 3 wherein the two parts ofthe pressure late have means arranged tobe interlocke by relativerotation of the parts in one direction, sai-d interlocking meanspermitting limited movement of one part relative to the other axially,the means for actuating said pressure platev having a positiveconnection with the rearward part thereof to allow the same to beadvanced or to retract the same, and serving to hold the forward partagainst relative yrotation with respect to the rearward part whilepermitting the limited relative axial movement referred to.

5. In a clutch structure as set forth in claim 3 wherein the meansinterconnecting the two parts of the pressure plate comprises lugs onone part and lugs on the other part providing recesses to interlock withthe lugs on the Hrst mentioned part when one part is rotated relative tothe other to a certain definite position, the said recesses permittinglimited axial movement of one art relative to the other, the provision oregistering openings in said parts, and pins received in saidsopeningsserving to maintain the two parts against relative rotation from theirinterlockedy losition.

6. In a c utch structure as set forth in claim 3 wherein the meansinterconnecting the two parts of the pressure plate comprises artproviding recesses to interlock with the Il)ugs on the first mentionedpart when one part is rotated relative to the other part to a certaindefinite position, the said recesses permitting limited axial movementof'one part relative to the other, the provision of egistion between thepressurefplate as a. whole tering openings in said parts, and pins reandthe back plate and constituting elements ceived in said openings servingto maintain of the said means for actuating the pressure l0 the twoparts against relative rotation from plate. v f

5 their interlockedposition, said ins being In witness-ofthe foregoing Iaix my received also in openings provi ed in the signature. Y back platewhereby to prevent relative rota- CHARLES A. STICKNEY.

